Paul Nyman is the chief popularizer of the Inverted W.

He is the person who, in his quest to sell pitchers what they wanted to buy -- velocity and more velocity -- identified the Inverted W as one reliable way of increasing a pitcher's velocity.

Paul Nyman recently published a multi-part defense of the Inverted W...

Comments on Nyman's Defense of the Inverted W

I thought it would be helpful if I went through Paul Nyman's defense of the Inverted W and commented on the more important parts of it.

There is no accredited research or study even hinting to the inverted W increasing probability of arm injury. Explanations put forth, as to the evils of the inverted W, are at best conjecture and are a misinterpretation of what the inverted W actually is.

As I say in my comments about Jeff Passan's Inverted W tweet, this is true in only the most technical of senses.

In my capstone piece on the Inverted W I explain that the problem with it and the other inverted arm actions isn't the position itself, but the Timing problem that getting to and passing through that position tends to create.

Which is something I've been saying since 2007.

As I explained in late 2007 in my analysis of Mark Prior's pitching mechanics, and more recently in my analysis of Stephen Strasburg's pitching mechanics...

The Inverted W isn't (necessarily) a problem in and of itself.

Rather, the Inverted W contributes to injuries in pitchers by creating a timing problem, and timing problems are what tend to hurt pitchers' arms.

While it may have been true a few years ago that there were no studies tying Timing problems to injuries, as I lay out in some detail in my piece The Scientific Basis of The Epidemic, over the past few years a number of studies have been done that back up the theory that the Inverted W is problematic if it creates a Timing problem.

Which it often does.

The study found that, as I explain in multiple places on my web site, the problem with the Inverted W isn't the arm action per se. Rather, the problem with the Inverted W is that it can create a Timing problem where the pitcher's arm isn't up and in the correct position when their front foot lands and their shoulders start to rotate, and that timing problem is what creates the problem.

As an aside, I believe the picture above was intended to show Stephen Strasburg. However, it actually shows Jarred Cosart. That isn't a huge point, except that it suggests that Jarred Cosart is at an elevated risk of experiencing an elbow or shoulder injury, especially if he is used as a starting pitcher.

(T)he inverted W was NEVER defined as lifting the elbow above the shoulder. It is simply a way of describing a throwing motion that starts as soon as the ball was taken out of the glove.

The problem with this contention is that, if the elbows don't go above the shoulders, then there is no need to describe the resulting shape as "inverted."

Back in the day (e.g. 2006-ish), Paul Nyman and I went around and around on this point.[1] I stated multiple times that I had no problem teaching the Horizontal W, because I could see it in the arm actions of Greg Maddux and Nolan Ryan, among others. However, when I pointed out the clear difference between what Nolan Ryan did and what Mark Prior did, Paul stated that there was no difference; that the different height of the elbows was inconsequential.

(W)hat is perceived as the elbow above the shoulder, is based upon the perception that the height of the shoulder remains fixed.

First, in the prior quote Paul says that lifting the elbows above the shoulders is not part of the Inverted W. However, if that is true, then why make the point directly above that what is going on the perception of lifting the elbows, not any actual lifting of the elbows?

Second, while the scapula is capable of moving around on the torso, pitchers who make the Inverted W tend to do so beyond the upward limits of the scapula. They also often do so with the elbows well behind the acromial plane, which increases the stress on the shoulder complex.

Third, and probably the most important, is the most stressful part of the delivery, as defined by the potential for arm injury, occurs long after what is perceived as elbow above the shoulder.

As I have explained for years, and as recent research demonstrates, the problem with the Inverted W isn't the position in and of itself. Instead, the problem is with the Inverted W's impact on the pitcher's timing; the Inverted W significantly increases the odds that the pitcher will experience a timing problem.

(T)he inverted W was simply a way of trying to describe that Smoltz initiated his throwing action as soon as his hands started to separate. It was not a rigid, single-purpose description such as elevating the elbow above the shoulders.

There is no need to describe the arm action as the Inverted W, and not the Horizontal W, if the elbows do not get above the shoulders. If the elbows do not get above the level of the shoulders, then the W isn't inverted.

I went around and around with Paul on this, trying to convince him that what Nolan Ryan, Greg Maddux, and other durable pitchers did was best described as a Horizontal W, and that it was very different than what John Smoltz, Mark Prior, and Billy Wagner did. To lump together Nolan Ryan, Greg Maddux, John Smoltz, Mark Prior, Billy Wagner, and others, as Paul did at the time and still seems to be trying to do, simply isn't accurate.

The inverted W was only one member of the “W family”. There is the inclined W, the “flat W” in contrast to a slinging (goalpost) initiation of the throwing process.

Again, during our disagreements, I tried to convince Paul Nyman of the value of the Horizontal W (aka the Flat W) and that that was a better description of what you saw in the arm action of Nolan Ryan. However, Paul insisted that the Horizontal W was not an accurate description of the arm action of any of the hardest throwers.

If you compare Strasburg and (Mariano Rivera) at (the) same point in the delivery, the point at which they achieve maximum external rotation, you will see that there is virtually no difference in elbow position with respect to the shoulder. From the research studies we know that at this point where both pitches of achieved maximum external rotation is the point in the delivery where maximum stress on the UCL occurs.

While this is true, it's also largely irrelevant. While there are some relevant differences in terms of the degree of external rotation that each achieves, the key difference between Stephen Strasburg and Mariano Rivera isn't that they get to that position of external rotation.

Rather, the difference is how they get to that position.

One thing that Paul Nyman relied upon when putting his ideas together are simulations like the one below.

The problem with simulations is that they don't always reflect reality.

While the simulation above shows a pitcher employing an inverted arm action, but still maintaining good timing, the fact is that most pitchers who employed such an arm action wouldn't demonstrate that timing.

Instead, they would exhibit a timing problem.

Paul Nyman's comments about the anatomy of the shoulder, and how it moves, don't prove anything other than that he hasn't read my work.

Based on what I have found by reading the research and studying pitchers, I have been saying for years that the problem with the Inverted W isn't the position itself; while the Inverted W is relatively uncomfortable, the mere act of making the Inverted W isn't what is causing problems in pitchers. Rather, the problem with the Inverted W is that is can create a timing problem, and that timing problem is what does the damage.

The contention on the part of the inverted W critics is that Mark Prior injured (his) shoulder because of the Inverted W. Considering Prior’s injury record, is it possible that his shoulder problems were a simply a result of wear and tear?

In criticizing the theory, people like Paul Nyman seem to believe, or would lead you to believe, that the theory is entirely based on the experiences of Mark Prior. That means that, if they pointed out how the case of Mark Prior is confounded, they can discredit the entire theory.

However, the theory about the Inverted W isn't dependent on Mark Prior.

As I explain in my piece Mark Prior, Anthony Reyes, and Causation, at the same time that Mark Prior was at USC and was being taught the Inverted W by Tom House, Anthony Reyes was also at USC and being taught the same thing.[2] As a result, Anthony Reyes ended up with a significant Inverted W, and arguably an even more dramatic one.

Anthony Reyes

As it turned out, while Anthony Reyes lasted a bit longer than Mark Prior -- presumably because he wasn't abused as much as Mark Prior was -- Reyes eventually went down with simultaneous elbow and shoulder injuries that he never recovered from.

With respect to Strasburg, I watched videotape of the game where it is believed he tore his UCL. What is interesting to me is that the pitch that he threw before having to come off the mound was a change up. Anyone who has thrown effective changeup understands that the grip on the changeup and delivery is different, which has the potential to change the forces on the elbow. Also the pitch prior to the changeup was a fastball where Strasburg exhibited no indication or sign of discomfort.

If Paul Nyman isn't familiar with the concept of the straw that broke the camel's back, then he should be. 

As Paul Nyman knows, or should know, the UCL is a bundle of a large number of fibers. The UCL doesn't rupture as the result of any one pitch. Rather, the UCL ruptures due to the fact that, with every high-effort throw, more fibers are ruptured than the body can repair before the next pitching session. As a result, over time the UCL gradually weakens until it reaches the point where the load on the UCL exceeds the capabilities of the degraded UCL and it ruptures.

About This Document

This essay is part of my in-progress Inverted W Webbook. This webbook, which is currently a work in progress, brings together all of the research that I have done into the Inverted W, why it is problematic, and how to manage and fix it.


1. You can view the exchanges between Paul Nyman and me over the years by searching for or I usually post under my name while Paul posts under justthefacts or coach xj.

2. I have been contacted by pitchers who have pitched for Tom House at USC and I know for a fact that Tom House taught, at least up until relatively recently, the Inverted W.